JP2017096182A - Multistage pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress vibration of diffuser blades, to arbitrarily design the shape of opening portions of the diffuser blades, and to easily perform surface processing and the like.SOLUTION: In a multistage pump, impellers 102 and a casing 108 accommodating the impellers are disposed in multistage. The multistage pump includes the impellers, and guide vanes 204 disposed at a wake flow side of the impellers in the casing, the guide vanes include base plates 201 and a plurality of diffuser blades 203 extended from the base plates, and have the open shape opened at end portions opposite to the base plates, of the diffuser blades. At least a part of pairs of the diffuser blades adjacent to each other includes a connection structure 200 for connecting and fixing the opened end portions of the diffuser blades to each other.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a multistage pump, and more particularly to a multistage pump having an open-shaped guide vane in a casing.

  There is a multistage pump as a pump capable of transferring a liquid at a high pressure of several MPa to several tens of MPa. High-pressure multistage pumps are used in a variety of applications, for example, to transfer hazardous liquids at high pressures.

  FIG. 5 is an enlarged cross-sectional view of the multistage pump disclosed in Patent Document 1. In a multistage pump in which the impeller 13 and the casing 16 that houses the impeller 13 are arranged in multiple stages, a spiral chamber 76a in the casing 64, and an open guide vane 77 having a front surface open to the downstream side of the spiral chamber 76a. And the impeller 13 has an open shape with the entire surface open, and the main plate 74 of the impeller 13 constitutes a partition wall between the spiral chamber 76 a and the return flow path 76 b formed by the guide vane 77.

  Patent Document 2 includes a multi-stage impeller, a multi-stage middle trunk that houses the impeller, a middle trunk cover that houses the middle trunk, an outer casing that surrounds the middle trunk and the middle trunk cover, and a middle trunk cover. A multistage pump including a fixing mechanism for fixing to a middle body is disclosed. The multistage pump includes a plurality of impellers fixed to a shaft. Guide vanes are arranged inside each middle cylinder so as to guide the liquid pressurized by the impeller of each stage to the impeller of the next stage.

JP-A-6-323289 JP 2013-213493 A

  The inventor has intensively studied to improve the structure of the multistage pump. As a result, the following knowledge was obtained.

  The guide vane located at the exit of the impeller generally has a complicated structure similar to a sandwich in which a diffuser blade is sandwiched between two plate members extending in a plane direction perpendicular to the axial direction. Therefore, the opening is narrow with respect to the liquid traveling direction, and the liquid intake efficiency is poor. Furthermore, since the structure is complicated, the processing accuracy and surface finishing accuracy tend to be low when manufacturing by casting and welding. In this way, since high technology is required for manufacturing, the cost increases. The cost increases as the number of stages increases.

  In the structure of the guide vane, it is conceivable that the diffuser blade usually sandwiched between two plate members is omitted from the plate member on one side, that is, one end of the diffuser blade is opened to form an open guide vane. In this case, the shape of the opening can be freely designed as much as the plate material is unnecessary. As a result, a design that can efficiently convert the velocity head into a pressure head is possible.

  However, it has been found that when such a configuration is adopted, the diffuser blades are likely to vibrate, and as a result, energy efficiency may be reduced or the diffuser blades may be damaged. The diffuser blade is located in the vicinity of the exit of the impeller, and the liquid discharged from the impeller directly flows in. When one end of the diffuser blade is opened, the diffuser blade is likely to vibrate due to a large influence of the flow velocity fluctuation.

  For this reason, it seems that it is difficult to use open-type guide vanes, especially in multistage pumps that handle high-pressure fluid. However, further studies have led to the idea that vibration can be suppressed even in an open guide vane.

  That is, the problem to be solved by the present disclosure is to suppress the vibration of the diffuser blade while adopting an open-shaped guide vane in a multistage pump.

  A multi-stage pump according to the present disclosure is a multi-stage pump in which an impeller and a casing that accommodates the impeller are arranged in multiple stages, and the multi-stage pump includes the impeller and the rear of the impeller in the casing. A guide vane provided on the flow side, the guide vane having a substrate and a plurality of diffuser blades extending from the substrate, and having an open shape in which an end portion of the diffuser blade facing the substrate is opened. And at least a part of the pair formed by the diffuser blades adjacent to each other, the coupling structure for coupling and fixing the opened end portions of the diffuser blades to each other.

  In the multistage pump, the number of diffuser blades provided in each stage may be an even number, and the coupling structure may be provided for every other pair of diffuser blades adjacent to each other.

  The multi-stage pump may include an odd number of diffuser blades included in each stage, and the coupling structure may include a portion that joins and fixes the open ends of three diffuser blades continuous in the circumferential direction. .

  In the multistage pump, the coupling structure may be configured integrally with the diffuser blade.

  In the multistage pump, the coupling structure may be such that a coupling member separate from the diffuser blades is coupled to the diffuser blades via a weld.

  According to the multistage pump according to the present disclosure, the vibration of the diffuser blades can be effectively suppressed by connecting the diffuser blades. On the other hand, since the end portion of the diffuser blade is open at a portion other than the coupling structure, the shape of the opening portion can be freely designed, and surface processing and the like are facilitated.

FIG. 1 is a cross-sectional view illustrating an example of a schematic configuration of the multistage pump according to the first embodiment. FIG. 2 is a partial cross-sectional view showing an example of a schematic configuration of the multistage pump of FIG. FIG. 3A is a plan view illustrating an example of a schematic configuration of an impeller and guide vanes included in the multistage pump according to the first embodiment. FIG. 3B is a plan view illustrating an example of a schematic configuration of a return flow path included in the multistage pump according to the first embodiment. FIG. 4 is a partially enlarged perspective view illustrating an example of a schematic configuration of a guide vane included in the multistage pump according to the first embodiment. FIG. 5 is a partial cross-sectional view showing an example of a schematic configuration of a conventional multistage pump.

  Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples, and do not limit the present disclosure.

Each of the embodiments described below shows a desirable specific example of the present disclosure. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and do not limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present disclosure are described as arbitrary constituent elements that constitute a more desirable form. In the drawings, the same reference numerals are sometimes omitted. In addition, the drawings schematically show each component for easy understanding, and there are cases where the shape, dimensional ratio, and the like are not accurately displayed. Moreover, in a manufacturing method, the order of each process etc. can be changed as needed, and another well-known process can be added.
(First embodiment)

  The first multistage pump is a multistage pump in which an impeller and a casing that accommodates the impeller are arranged in multiple stages. The multistage pump is provided in the casing on the downstream side of the impeller and the impeller. The guide vane includes a substrate and a plurality of diffuser blades extending from the substrate. The diffuser blade has an open shape by opening an end of the diffuser blade facing the substrate, and the diffuser blades are adjacent to each other. In at least a part of the pair formed by the blades, a coupling structure is provided that bonds and fixes the open ends of the diffuser blades together.

  The second multi-stage pump is a first multi-stage pump, wherein the number of diffuser blades provided in each stage is an even number, and a coupling structure is provided for every other pair of diffuser blades adjacent to each other. .

  The third multi-stage pump is a first multi-stage pump, wherein the number of diffuser blades provided in each stage is an odd number, and the coupling structure is configured to connect the open end portions of the three diffuser blades continuous in the circumferential direction. It includes parts that are fixed together.

  The fourth multistage pump is any one of the first to third multistage pumps, and the coupling structure is formed integrally with the diffuser blades.

  The fifth multi-stage pump is any one of the first to third multi-stage pumps, and the coupling structure has a coupling member that is separate from the diffuser blades and is coupled to the diffuser blades via a weld.

  The coupling structure can be manufactured by machining or welding together with the guide vanes. The coupling structure may be an arc-shaped coupling member smaller than the main plate of the diffuser blade. The coupling structure can be arranged at a position close to the axis. The coupling structure can be arranged in a portion of the diffuser blade closest to the rotating blade of the impeller. The plurality of coupling structures may be fixed at the same distance in the radial direction from the rotation axis.

  FIG. 1 is a cross-sectional view illustrating an example of a schematic configuration of the multistage pump according to the first embodiment. FIG. 2 is a partial cross-sectional view showing an example of a schematic configuration of the multistage pump of FIG. FIG. 3A is a plan view illustrating an example of a schematic configuration of an impeller and guide vanes included in the multistage pump according to the first embodiment. FIG. 3B is a plan view illustrating an example of a schematic configuration of a return flow path included in the multistage pump according to the first embodiment. FIG. 4 is a partially enlarged perspective view illustrating an example of a schematic configuration of a guide vane included in the multistage pump according to the first embodiment. Hereinafter, the multistage pump 100 of the first embodiment will be described with reference to FIGS. 1 to 4.

  As shown in the figure, the multistage pump 100 includes an impeller 102, a casing 108, and guide vanes 204.

  The impeller 102 and the guide vane 204 are disposed in the casing 108.

  The guide vane 204 is provided on the downstream side of the impeller 102. In the example shown in the figure, the guide vane 204 is provided on the outer peripheral side of the impeller 102. In other words, the guide vane 204 is provided on the radially outer side of the impeller 102 so as to surround the impeller 102.

  The guide vane 204 includes a substrate 201 and a plurality of diffuser blades 203 extending from the substrate 201. The guide vane 204 has an open shape. Specifically, the end of the diffuser blade 203 facing the substrate 201 is opened, so that the guide vane 204 has an open shape. “Open” means, for example, that the surface is not closed.

  Further, the guide vane 204 includes a coupling structure 200. The coupling structure 200 couples and fixes the open ends of the diffuser blades 203 to each other in at least a part of a pair formed by adjacent diffuser blades 203.

  The number of the diffuser blades 203 included in each stage may be an even number, and the coupling structure 200 may be provided for every other pair of diffuser blades 203 adjacent to each other.

  The number of the diffuser blades 203 included in each stage may be an odd number, and the coupling structure 200 may include a portion that joins and fixes the open ends of the three diffuser blades 203 that are continuous in the circumferential direction. In this case, in the remaining diffuser blades 203, the coupling structure 200 may be provided for every other pair of diffuser blades 203 adjacent to each other.

  Hereinafter, a more specific configuration example of the multistage pump 100 will be described with reference to FIGS. 1 to 4. In addition, the following description demonstrates the example of 1 structure of the multistage pump 100, Comprising: The multistage pump of 1st Embodiment is not limited to the structure demonstrated below.

  The multistage pump 100 includes a plurality of impellers 102 fixed to a shaft 101. A plurality of inner cylinders 103 are arranged so as to surround the impeller 102. A guide vane 204 and a return flow path 115 are provided inside each middle cylinder 103. The flow path in the guide vane 204 and the return flow path 115 are connected by the through flow path 202 so that the liquid pressurized by the impeller 102 at each stage is guided to the impeller 102 at the next stage. . The middle drums 103 are overlapped along the axial direction (direction in which the shaft 101 extends), and these middle drums 103 are fixed to each other by a plurality of through bolts 150. Further, a casing 108 is disposed so as to surround these inner cylinders 103. The casing 108 is provided with a liquid suction port 109 and a discharge port 110. The inner cylinder 103 and the casing 108 constitute a double casing structure.

  An end portion of the shaft 101 is connected to a driving machine (for example, a motor) (not shown), and the impeller 102 is rotated by this driving machine. When the impeller 102 rotates, liquid is sucked from the suction port 109 and guided to the impeller 102, and the pressure is sequentially increased by each impeller 102. The space between the middle cylinder 103 and the casing 108 is filled with the pressurized liquid, and the liquid is discharged from the discharge port 110. Thus, the middle cylinder 103 has a function of partitioning the liquid being pressurized and the pressurized liquid, and the casing 108 has a function of preventing leakage of the pressurized liquid to the outside.

  FIG. 2 is a schematic cross-sectional view showing a part of the multistage pump shown in FIG. As shown in FIG. 2, middle cylinders 103 </ b> A to 3 </ b> D having the same number of stages as the impeller 102 are overlapped. Positioning pins 107 are mounted between the middle cylinders and the guide vanes 204 and the return flow path 115, and the relative positions of the middle cylinders 103 </ b> A to 103 </ b> D, the guide vanes 204 and the return flow paths 115 are set by the positioning pins 107. It is fixed. An annular gasket 114 is disposed between the end surface of the first-stage inner cylinder 103 </ b> A and the casing 108. A pressing member 112 is disposed adjacent to the middle drum 103D of the final stage, and a diffuser 113 is formed inside the pressing member 112 so as to surround the impeller 102 of the final stage. The middle cylinders 103A to 103D and the pressing member 112 are fastened to each other by a plurality of through bolts 150 (only one through bolt 150 is shown in FIG. 2).

  The liquid pressurized by the rotation of the impeller 102 presses the pressing member 112 and the inner cylinders 103 </ b> A to 103 </ b> D toward the suction side, whereby the end surface of the first intermediate cylinder 103 </ b> A presses the gasket 114 against the casing 108. As described above, the gasket 114 sandwiched between the first-stage inner cylinder 103A and the casing 108 functions as a seal that prevents the pressurized liquid from flowing into the region on the suction side.

  In the example shown in FIG. 3A, five rotating blades 104 are fixed to one impeller 102. The impeller 102 is fixed to the shaft 101, and the rotating blade 104 rotates as the shaft 101 rotates.

  A single guide vane 204 is provided outside the single impeller 102 as viewed from the axial direction. Even if the shaft 101 rotates, the guide vane 204 is fixed. Twelve diffuser blades 203 are fixed to the guide vane 204. By fastening the through bolt 150, the diffuser blade 203 is pressed against the wall of the middle drum 103 (a wall extending inwardly from the casing 108 in a direction perpendicular to the shaft 101), so that the wall, the substrate 201, and a pair of A flow path surrounded by the diffuser blades 203 is formed. A through channel 202 is formed at the downstream end of the channel. The through channel 202 is a channel that penetrates the substrate 201. The through channel 202 penetrates the substrate 201 at the outer periphery of the guide vane 204.

  The substrate 201 extends in a plane direction perpendicular to the axis 101 of the multistage pump 100. The diffuser blade 203 extends in a direction perpendicular to the substrate 201 (a direction parallel to the axis 101). However, the diffuser blade 203 may extend obliquely with respect to the substrate 201. When the substrate 201 is placed horizontally so that the diffuser blade 203 extends upward, the upper end of the diffuser blade 203 is open. In this case, the coupling structure 200 fixes the upper ends of the diffuser blades 203 to each other.

  In the example shown in the figure, the coupling structure 200 is a bar extending along the inner periphery of the guide vane. In the example shown in the figure, one coupling structure 200 is provided for each pair of diffuser blades 203, but a plurality of coupling structures 200 may be provided for each pair of diffuser blades 203. The coupling structure 200 and the diffuser blade 203 may form the same plane at the upper ends. With such a configuration, sealing with the wall of the middle trunk 103 is facilitated.

  The coupling structure 200 may be configured integrally with the diffuser blade 203 by cutting or the like. Alternatively, the coupling structure 200 may be configured such that a coupling member separate from the diffuser blade 203 is coupled to the diffuser blade 203 via a welded portion by welding.

  The coupling structure 200 may be provided, for example, so as to fix all the diffuser blades 203 to each other for each stage. In this case, the coupling structure 200 may have a ring shape, that is, a circumference in a plan view.

  In a configuration (closed shape) in which the opposite side of the diffuser blade 203 to the substrate 201 is entirely covered with a plate material (closed shape), processing is difficult and surface processing accuracy is likely to deteriorate. On the other hand, in a configuration in which the side opposite to the substrate 201 of the diffuser blade 203 is open over the entire surface (conventional open shape), the diffuser blade 203 is likely to vibrate during pump operation, and the diffuser blade 203 may be damaged by the vibration. It was.

  As in the present embodiment, by providing the coupling structure 200 only at a part of the open end of the diffuser blade 203 (semi-open shape), not only vibration is suppressed, but processing becomes easier, and the surface Processing accuracy and surface finishing accuracy can be easily increased.

  In the example shown in FIG. 4, the upper end of the diffuser blade 203 </ b> A and the upper end of the diffuser blade 203 </ b> B are coupled and fixed by a coupling structure 200 at a part (the end portion on the impeller 102 side in the illustrated example). The substrate 201, the diffuser blade 203A, the diffuser blade 203B, and the coupling structure 200 form an opening 206 that faces the impeller 102 (toward the shaft 101). When the substrate 201 is placed so as to form a bottom surface in the horizontal direction, the guide vane 204 has an opening 205 directed upward between the diffuser blade 203A and the diffuser blade 203B. The shape, thickness, material, and the like of the coupling structure 200 can be appropriately set to such an extent that the vibration of the diffuser blade 203 can be appropriately suppressed.

  In the example shown in FIG. 3B, twelve return guide vanes 105 are fixed to the surface of the substrate 201 opposite to the diffuser vanes 203. A return flow path 115 is formed between the return guide blades 105. A through channel 202 is formed at the upstream end of the return channel 115. The side opposite to the substrate 201 of the return guide vane 105 is sealed by a wall of the inner drum 103 (a wall extending inwardly from the casing 108 in a direction perpendicular to the shaft 101), but the shaft 101 side has a circumferential shape. An opening is formed. Through the opening, liquid flows from the return flow path 115 to the impeller 102 (see FIG. 2). The return flow path 115 and the guide vane 204 may be composed of the same member, or may be composed of different members.

  In the configuration of the first embodiment, a large opening can be taken and vibration can be efficiently suppressed. Further, the manufacturing is easy and the cost can be reduced.

  From the above description, many modifications and other embodiments of the present disclosure are apparent to persons skilled in the art. Accordingly, the foregoing description is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the disclosure. Details of the structure and / or function may be substantially changed without departing from the spirit of the present disclosure.

13 impeller 16 casing 74 main plate 77 guide vane 76a swirl chamber 76b return flow path 100 multistage pump 101 shaft 102 impeller 103 inner cylinder 104 rotary blade 105 return guide vane 107 positioning pin 108 casing 109 suction port 110 discharge port 112 pressing member 113 Diffuser 114 Gasket 115 Return flow path 150 Through bolt 200 Bonding structure 201 Substrate 202 Through flow path 203 Diffuser blade 204 Guide vane 205 Opening 206 Opening

Claims (5)

A multistage pump in which an impeller and a casing for housing the impeller are arranged in multiple stages,
The multi-stage pump includes the impeller and a guide vane provided on the downstream side of the impeller in the casing.
The guide vane is
A substrate and a plurality of diffuser blades extending from the substrate;
An open shape in which an end portion of the diffuser blade facing the substrate is opened, and
A coupling structure for coupling and fixing the open ends of the diffuser blades to each other in at least a part of a pair formed by the diffuser blades adjacent to each other;
Multistage pump. The number of the diffuser blades provided in each stage is an even number;
The coupling structure is provided for every other pair of the diffuser blades adjacent to each other.
The multistage pump according to claim 1. The number of the diffuser blades included in each stage is an odd number,
The coupling structure includes a portion that couples and fixes the open ends of the three diffuser blades that are continuous in the circumferential direction.
The multistage pump according to claim 1.   The multi-stage pump according to claim 1, wherein the coupling structure is configured integrally with the diffuser blade.   The multi-stage pump according to any one of claims 1 to 3, wherein the coupling structure includes a coupling member separated from the diffuser blades and coupled to the diffuser blades via a weld.